Paste-like adhesive composition

Abstract

To achieve both the adhesive properties of a paste-like adhesive composition and the reduced fillet creep.SOLUTION: A paste-like adhesive composition used for bonding a semiconductor element having a thickness of 200 μm or less onto a substrate includes a polymerizable compound and a particulate filler, in which the composition has a viscosity η5 of 15,000 mPa s or more and 50,000 mPa s or less when measured at 25°C using a Brookfield viscometer at a rotation speed of 5 rpm, and a ratio η0.5 / η5 being a viscosity η0.5 when measured at 25°C using the Brookfield viscometer at a rotation speed of 0.5 rpm to η5 is 1.5 or more and 4.0 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a paste adhesive composition. [Background technology]

[0002] Various die-bonding materials for semiconductor devices have been developed to date. One example of this type of technology is described in Patent Document 1. This document describes that gold powder and ester alcohol are used as the die-attach material, and that sintering under certain conditions allows for sintering at a relatively low temperature. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-324523 Summary of the Invention [Problem to be solved by the invention]

[0004] The present inventors have investigated the use of a paste adhesive composition for bonding semiconductor elements to substrates, and have found that there is room for improvement in terms of both the adhesiveness of the paste adhesive composition and the reduction of creeping up of the paste adhesive composition onto semiconductor elements (hereinafter referred to as "fillet creeping up"). [Means for solving the problem]

[0005] The present inventors have investigated the viscosity of paste adhesive compositions in order to achieve both adhesiveness and reduced fillet creeping. As a result, it has been found that the viscosity η5 measured at 25°C using a Brookfield viscometer at a rotation speed of 5 rpm is 15,000 mPa·s or more and 50,000 mPa·s or less, and the viscosity η5 measured at 25°C using the Brookfield viscometer at a rotation speed of 0.5 rpm is 15,000 mPa·s or more and 50,000 mPa·s or less. 0.5 and η, which is the ratio of η5 0.5It has been found that by adjusting / η5 to 1.5 or more and 4.0 or less, it is possible to achieve both the adhesiveness of the paste adhesive composition and the reduction of fillet creep-up.

[0006] According to the present invention, the following paste adhesive composition is provided. [1] A paste-like adhesive composition used for adhering a semiconductor element having a thickness of 200 μm or less to a substrate, a polymerizable compound; a particulate filler; Including, The viscosity η5 measured at 25°C using a Brookfield viscometer at a rotation speed of 5 rpm is 15,000 mPa s or more and 50,000 mPa s or less, Viscosity η measured at 25°C using the Brookfield viscometer at a rotation speed of 0.5 rpm 0.5 and η, which is the ratio of η5 0.5 A paste-like adhesive composition, characterized in that / η5 is 1.5 or more and 4.0 or less. [2] [1] A paste-like adhesive composition according to the present invention, A paste-like adhesive composition having a coverage of 95% or more as defined by the following condition 1. [Condition 1] 1. Prepare a wafer (material: silicon, length, width, height: 4 mm x 4 mm x 0.2 mm) and a substrate. 2. The paste adhesive composition is applied to a rectangular area (4 mm x 4 mm) on the substrate where the wafer is to be placed, along the diagonal of the rectangular area, to a length of 4.5 mm, a width of 0.8 mm, and a thickness of 0.1 mm. 3. The wafer is placed on the rectangular area to which the paste adhesive composition has been applied. 4. Five minutes after the wafer is mounted, the ratio [%] of the rectangular area to the entire rectangular area that is coated with the paste adhesive composition is defined as the coverage rate. [3] [1] or [2], wherein the paste-like adhesive composition is A paste-like adhesive composition having a capillary fill property of 5 minutes or less as defined by the following condition 2. [Condition 2] 1. Prepare a wafer (material: silicon, length, width, height: 4 mm x 4 mm x 0.2 mm) and a substrate. 2. The paste adhesive composition is applied to a rectangular area (4 mm x 4 mm) on the substrate where the wafer is to be placed, along the diagonal of the rectangular area, to a length of 4.5 mm, a width of 0.8 mm, and a thickness of 0.1 mm. 3. The wafer is placed on the rectangular area to which the paste adhesive composition has been applied. 4. The time t [min] from when the wafer is mounted until the proportion of the rectangular area coated with the paste adhesive composition reaches 95% of the entire rectangular area is defined as the "capillary fillability." [4] A paste-like adhesive composition according to any one of [1] to [3], A paste-like adhesive composition, wherein the polymerizable compound comprises a compound having an epoxy group or a compound having a polymerizable double bond group. [5] [4] A paste-like adhesive composition according to the present invention, A paste-like adhesive composition, wherein the polymerizable compound comprises an acrylic acid ester. [6] [1] to [5], wherein the paste-like adhesive composition is A paste adhesive composition, wherein the particulate filler is conductive particles. [7] [6] A paste-like adhesive composition according to the present invention, A paste adhesive composition in which the particulate filler has at least a portion of its surface made of silver or copper. [8] A paste-like adhesive composition according to any one of [1] to [7], The paste adhesive composition, wherein the particulate filler is insulating particles. [9] [8] A paste-like adhesive composition according to the present invention, The particulate filler is a paste adhesive composition comprising at least one material selected from the group consisting of silicon dioxide, boron nitride, alumina, and an organic material.

[10] [1] to [9], wherein the paste-like adhesive composition is The paste adhesive composition, wherein the particulate filler is composed of at least one of spherical particles, polygonal particles, flake-like particles, dendritic particles, and scale-like particles.

[11] [1] to

[10] , wherein the paste-like adhesive composition is A paste-like adhesive composition in which the particulate filler has a particle diameter D50 of 0.1 μm or more and 20 μm or less, at which the cumulative frequency is 50% in a volume-based cumulative frequency distribution curve measured using a laser diffraction particle size distribution measuring device. [Effects of the Invention]

[0007] According to the present invention, a paste adhesive composition is provided which achieves both the adhesiveness of a paste adhesive composition and the reduction of fillet creep-up. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of the present invention will be described. The paste adhesive composition according to the present embodiment is a paste adhesive composition used for bonding a semiconductor element having a thickness of 200 μm or less to a substrate, and contains a polymerizable compound and a particulate filler. The semiconductor element is, for example, a semiconductor chip.

[0009] Furthermore, the paste adhesive composition according to this embodiment has a viscosity η5 measured at 25°C using a Brookfield viscometer at a rotation speed of 5 rpm of preferably 15,000 mPa·s or more and 50,000 mPa·s or less, more preferably 18,000 mPa·s or more and 47,000 mPa·s or less, and even more preferably 19,000 mPa·s or more and 45,000 mPa·s or less.

[0010] Furthermore, the paste adhesive composition according to this embodiment has a viscosity η measured at 25°C using the B-type viscometer at a rotation speed of 0.5 rpm. 0.5 and η, which is the ratio of η5 0.5 / η5 is preferably 1.5 or more and 4.0 or less, more preferably 1.6 or more and 3.9 or less, and even more preferably 1.7 or more and 3.8 or less.

[0011] The paste-like adhesive composition according to this embodiment is a mixture of η5 and η 0.5 When / η5 is within the above range, the adhesiveness of the paste adhesive composition can be improved while reducing fillet creep-up.

[0012] Fillet creep refers to the creeping up of a paste adhesive composition onto a semiconductor element when the semiconductor element is bonded to a substrate. Fillet creep causes a decrease in the reliability of the bonded semiconductor element. This effect is particularly significant when bonding semiconductor elements with a thickness of 200 μm or less. The substrate may be, for example, a lead frame, an interposer substrate, a ceramic substrate, a metal substrate, or a composite substrate such as a DBC substrate or a DBA substrate.

[0013] Furthermore, the paste adhesive composition according to this embodiment preferably has a coverage of 95% or more, more preferably 97% or more, and even more preferably 98% or more, as measured under the following condition 1. When the coverage is within the above range, the paste adhesive composition can achieve even better adhesion. [Condition 1] 1. Prepare a wafer (material: silicon, length, width, height: 4 mm x 4 mm x 0.2 mm) and a substrate. 2. The paste adhesive composition is applied to a rectangular area (4 mm x 4 mm) on the substrate where the wafer is to be placed, along the diagonal of the rectangular area, to a length of 4.5 mm, a width of 0.8 mm, and a thickness of 0.1 mm. 3. The wafer is placed on the rectangular area to which the paste adhesive composition has been applied. 4. Five minutes after the wafer is mounted, the ratio [%] of the rectangular area to the entire rectangular area that is coated with the paste adhesive composition is defined as the coverage rate.

[0014] Furthermore, the capillary fill property of the paste adhesive composition according to this embodiment is preferably 5 min or less, more preferably 4.5 min or less, and even more preferably 4 min or less, as measured under the following condition 2. When the capillary fill property is within the above range, the paste adhesive composition can stably achieve excellent adhesiveness. [Condition 2] 1. Prepare a wafer (material: silicon, length, width, height: 4 mm x 4 mm x 0.2 mm) and a substrate. 2. The paste adhesive composition is applied to a rectangular area (4 mm x 4 mm) on the substrate where the wafer is to be placed, along the diagonal of the rectangular area, to a length of 4.5 mm, a width of 0.8 mm, and a thickness of 0.1 mm. 3. The wafer is placed on the rectangular area to which the paste adhesive composition has been applied. 4. The time t [min] from when the wafer is mounted until the proportion of the rectangular area coated with the paste adhesive composition reaches 95% of the entire rectangular area is defined as the "capillary fillability."

[0015] In the above-mentioned conditions 1 and 2, the rectangular area to which the paste adhesive composition is applied is the area in which the paste adhesive composition spreads, and the ratio of the rectangular area to which the paste adhesive composition is applied to the entire rectangular area can be calculated, for example, by image processing an image of the substrate taken from a vertical direction.

[0016] Next, the configuration of the paste adhesive composition of this embodiment will be described in detail.

[0017] [Polymerizable compound] The polymerizable compound according to this embodiment preferably includes a compound having an epoxy group or a compound having a polymerizable double bond group. For example, it preferably includes a monomer such as an epoxy monomer or an acrylic monomer, an epoxy resin, or an acrylic resin. As the polymerizable compound, one or a combination of two or more of the above specific examples may be used.

[0018] <Epoxy monomer> The epoxy monomer according to this embodiment has an epoxy group in its structure. The epoxy monomer may be a monofunctional epoxy monomer having only one epoxy group in its structure, or a polyfunctional epoxy monomer having two or more epoxy groups in its structure.

[0019] Specific examples of the monofunctional epoxy monomer include 4-tert-butylphenyl glycidyl ether, cresyl glycidyl ethers including m-cresyl glycidyl ether and p-cresyl glycidyl ether, phenyl glycidyl ether, etc. Among the above specific examples, one or a combination of two or more types can be used as the monofunctional epoxy monomer.

[0020] Specific examples of polyfunctional epoxy monomers include bisphenol compounds such as bisphenol A, bisphenol F, and biphenol, or derivatives thereof; alicyclic diols such as hydrogenated bisphenol A, hydrogenated bisphenol F, hydrogenated biphenol, cyclohexanediol, cyclohexanedimethanol, and cyclohexanediethanol, or derivatives thereof; epoxidized bifunctional aliphatic diols such as butanediol, hexanediol, octanediol, nonanediol, and decanediol, or derivatives thereof; trifunctional monomers having a trihydroxyphenylmethane skeleton or an aminophenol skeleton; and polyfunctional epoxidized phenol novolac resins, cresol novolac resins, phenol aralkyl resins, biphenyl aralkyl resins, and naphthol aralkyl resins. Polyfunctional epoxy monomers can be used alone or in combination of two or more of the above specific examples.

[0021] <Epoxy resin> Specific examples of epoxy resins include siloxane-based epoxy resins, trisphenolmethane-based epoxy resins, hydrogenated bisphenol A-based liquid epoxy resins, bisphenol-F-diglycidyl ether, and orthocresol novolac-based epoxy resins. The epoxy resins may be selected from the above specific examples, either individually or in combination. Of the above specific examples, the epoxy resin preferably contains a siloxane-based epoxy resin.

[0022] The upper limit of the weight-average molecular weight Mw of the epoxy resin is, for example, preferably 3000 or less, and more preferably 2000 or less. This improves the handleability of the paste adhesive composition. This is therefore preferable from the viewpoints that the paste adhesive composition can be uniformly applied and that inhibition of aggregation of the particulate filler due to non-uniformity of the paste adhesive composition can be suppressed. Furthermore, the lower limit of the weight-average molecular weight Mw of the epoxy resin is, for example, preferably 150 or more, and more preferably 200 or more. This can suppress inhibition of aggregation of the particulate filler from the same viewpoint as the above upper limit.

[0023] <Acrylic monomer> The acrylic monomer according to this embodiment is a monomer having a (meth)acrylic group in its structure. In this embodiment, the (meth)acrylic group refers to an acrylic group or a methacrylic group (methacrylate group). The acrylic monomer according to this embodiment may be a monofunctional acrylic monomer having only one (meth)acrylic group in its structure, or may be a polyfunctional acrylic monomer having two or more (meth)acrylic groups in its structure. In this embodiment, the acrylic group includes an acrylate group.

[0024] The monofunctional acrylic monomer preferably contains acrylate ester. Specific examples of the monofunctional acrylic monomer include 2-phenoxyethyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, isoamyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, n-lauryl (meth)acrylate, n-tridecyl (meth)acrylate, n-stearyl (meth)acrylate, isostearyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, butoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, 2-ethylhexyldiethylene glycol (meth)acrylate, and methoxypolyethylene glycol. (meth)acrylate, methoxydipropylene glycol (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, nonylphenol ethylene oxide modified (meth)acrylate, phenylphenol ethylene oxide modified (meth)acrylate, isobornyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate quaternized, glycidyl (meth)acrylate, neopentyl glycol (meth)acrylic acid benzoate, 1,Examples of suitable monofunctional acrylic monomers include 4-cyclohexanedimethanol mono(meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl hexahydrophthalate, 2-(meth)acryloyloxyethyl phthalate, 2-(meth)acryloyloxyethyl-2-hydroxyethyl phthalate, and 2-(meth)acryloyloxyethyl acid phosphate. Among the above specific examples, one or a combination of two or more can be used as the monofunctional acrylic monomer. Of the above specific examples, 1,4-cyclohexanedimethanol monoacrylate is preferably used as the monofunctional acrylic monomer. This allows the acrylic monomer to polymerize favorably, resulting in greater cure shrinkage of the paste-like adhesive composition. In this embodiment, (meth)acrylate refers to acrylate and methacrylate, methacrylic acid refers to acrylic acid and methacrylic acid, and (meth)acryloyl refers to acryloyl and methacryloyl.

[0025] Specific examples of polyfunctional acrylic monomers include ethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, propoxylated bisphenol A di(meth)acrylate, hexane-1,6-diol bis(2-methyl(meth)acrylate), 4,4'-isopropylidenediphenol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,6-bis((meth)acryloyloxy)-2,2,3,3,4 ,4,5,5-octafluorohexane, 1,4-bis((meth)acryloyloxy)butane, 1,6-bis((meth)acryloyloxy)hexane, triethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, N,N'-di(meth)acryloylethylenediamine, N,N'-(1,2-dihydroxyethylene)bis(meth)acrylamide, or 1,4-bis((meth)acryloyl)piperazine.

[0026] As the acrylic monomer, a monofunctional acrylic monomer or a polyfunctional acrylic monomer may be used alone, or a monofunctional acrylic monomer and a polyfunctional acrylic monomer may be used in combination. As the acrylic monomer, for example, it is preferable to use a polyfunctional acrylic monomer alone.

[0027] <Acrylic resin> The acrylic resin may be a liquid resin having two or more acrylic groups in one molecule. Specifically, the acrylic resin may be a polymer or copolymer of the above-mentioned acrylic monomers. The polymerization or copolymerization method is not limited, and a known method using a general polymerization initiator and chain transfer agent, such as solution polymerization, may be used. The acrylic resin may be used alone, or two or more different types with different structures may be used.

[0028] The acrylic resin may, for example, have an epoxy group, an amino group, a carboxyl group, and a hydroxyl group in its structure. If the acrylic resin has an epoxy group in its structure, it can react with a curing agent, which will be described later, and undergo cure shrinkage. If the acrylic resin has an amino group, a carboxyl group, or a hydroxyl group in its structure and contains an epoxy resin as a base resin, the acrylic resin and the epoxy resin can react and undergo cure shrinkage. The acrylic resin may, for example, have a carbon-carbon double bond C=C in its structure. If the acrylic resin has a carbon-carbon double bond in its structure, it can be involved in a polymerization reaction caused by a radical polymerization initiator and undergo cure shrinkage.

[0029] Specific examples of commercially available acrylic resins include ARUFON UG-4035, ARUFON UG-4010, ARUFON UG-4070, ARUFON UH-2000, ARUFON UH-2041, ARUFON UH-2170, and ARUFON UP-1000, all manufactured by Toagosei Co., Ltd.

[0030] The lower limit of the content of the polymerizable compound in the paste adhesive composition is, for example, preferably 15 parts by mass or more, more preferably 25 parts by mass or more, and even more preferably 30 parts by mass or more, per 100 parts by mass of the paste adhesive composition. The upper limit of the content of the polymerizable compound in the paste adhesive composition may be, for example, 99 parts by mass or less, or 90 parts by mass or less, per 100 parts by mass of the paste adhesive composition.

[0031] [Particulate filler] In this embodiment, the particulate filler is used to increase the mechanical strength and thermal conductivity of the cured product of the paste adhesive composition. Examples of the particulate filler that can be used include inorganic fillers and organic fillers.

[0032] The particulate filler is composed of at least one material selected from the group consisting of silicon dioxide, boron nitride, alumina, and organic materials. When the particulate filler is an inorganic filler, the particulate filler is composed of one or more materials selected from the group consisting of silicon dioxide, boron nitride, silver, and alumina. Among these, inorganic fillers composed of silver are particularly preferred because of their excellent balance between mechanical strength and thermal conductivity.

[0033] When the particulate filler is an organic filler, the particulate filler is composed of one or more materials selected from organic materials such as, for example, a cured thermosetting resin, heat-resistant thermoplastic polymer particles, and an elastomer.

[0034] Examples of thermosetting resin cured products include phenolic resin cured products, polyimide resin cured products, cashew dust, and epoxy resin cured products. Examples of heat-resistant thermoplastic resin polymer fine particles include nylon fine particles. Examples of elastomers include polyvinyl butyral and nitrile butadiene rubber. One type of organic filler may be used alone, or two or more types may be used in combination. Among these, it is preferable to use phenolic resin cured products from the viewpoint of high heat resistance and low thermal expansion.

[0035] Furthermore, the particulate filler may be either conductive particles or insulating particles. When the particulate filler is a conductive particle, the particulate filler is made of, for example, silver or copper. Alternatively, when the particulate filler is a conductive particle, at least a portion of the surface of the particulate filler is made of silver or copper. When the particulate filler is an insulating particle, the particulate filler is made of, for example, at least one of the above-mentioned silicon dioxide, boron nitride, alumina, and organic material.

[0036] In terms of shape, the particulate filler is preferably composed of at least one of spherical particles, polygonal particles, flake-like particles, dendritic particles, and scale-like particles.

[0037] Furthermore, the particle diameter D50 at 50% cumulative frequency in a volume-based cumulative frequency distribution curve of the particulate filler measured using a laser diffraction particle size distribution analyzer is preferably 0.1 μm or more and 500 μm or less, more preferably 0.1 μm or more and 20 μm or less, even more preferably 0.1 μm or more and 10 μm or less, and even more preferably 0.5 μm or more and 10 μm or less. By setting D50 to the above-mentioned lower limit or more, mechanical strength can be improved. On the other hand, by setting D50 to the above-mentioned upper limit or less, dispersibility can be improved and mechanical strength can be stabilized.

[0038] The upper limit of the specific surface area of ​​the particulate filler is, for example, 2.10 m 2 / g or less, and 1.05m 2 / g or less is more preferable, and 1.00m 2 It is more preferable that the molecular weight is 0.27m / g or less. 2 The lower limit of the specific surface area of ​​the particulate filler is, for example, 0.10 m 2 / g or more, and 0.20m 2 / g or more is more preferable, and 0.25m 2 It is more preferable that the saturation coefficient is 1 / g or more.

[0039] The upper limit of the tap density of the particulate filler is, for example, 10.0 g / cm 3 Preferably, it is 8.0 g / cm or less. 3 More preferably, it is 7.0 g / cm or less. 3 More preferably, it is 6.0 g / cm or less. 3 The lower limit of the specific surface area of ​​the particulate filler is, for example, 0.5 g / cm. 3 It is preferable that the concentration is 1.0 g / cm or more. 3 More preferably, it is 1.5 g / cm or more. 3 More preferably, it is equal to or greater than this.

[0040] The lower limit of the content of the particulate filler in the paste adhesive composition is, for example, preferably 65 parts by mass or more, more preferably 70 parts by mass or more, and even more preferably 75 parts by mass or more, per 100 parts by mass of the paste adhesive composition. This allows the cured product of the paste adhesive composition to exhibit suitable thermal conductivity. Furthermore, the upper limit of the content of the particulate filler in the paste adhesive composition may be, for example, 99 parts by mass or less, or 90 parts by mass or less, per 100 parts by mass of the paste adhesive composition. This allows the adhesive strength between the paste adhesive composition and the adherend to be suppressed from decreasing.

[0041] [Hardening agent] When the paste-like adhesive composition of the present embodiment contains an epoxy monomer or an epoxy resin as the polymerizable compound, it preferably contains, for example, a curing agent. As the curing agent, a phenol curing agent or an imidazole curing agent can be used.

[0042] <Phenol curing agent> Specific examples of phenolic curing agents include novolac-type phenolic resins such as phenol novolac resin, cresol novolac resin, bisphenol novolac resin, and phenol-biphenyl novolac resin; polyvinylphenol; multifunctional phenolic resins such as triphenylmethane-type phenolic resin; modified phenolic resins such as terpene-modified phenolic resin and dicyclopentadiene-modified phenolic resin; phenol aralkyl-type phenolic resins such as phenol aralkyl resins having a phenylene skeleton and / or biphenylene skeleton and naphthol aralkyl resins having a phenylene skeleton and / or biphenylene skeleton; bisphenol compounds such as bisphenol A and bisphenol F (dihydroxydiphenylmethane); and compounds having a biphenylene skeleton such as 4,4'-biphenol. The phenolic curing agent may include one or more types selected from the above specific examples.

[0043] <Imidazole curing agent> Specific examples of the imidazole curing agent include 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-1H-imidazole-4,5-dimethanol, 2-methylimidazole, 2-phenylimidazole, 2,4-diamino-6-[2-methylimidazolyl-(1)]-ethyl-s-triazine, 2-undecylimidazole, 2-heptadecylimidazole, 2,4-diamino-6-[2-methylimidazolyl-(1)]-ethyl-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-methylimidazole isocyanuric acid adduct, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2-undecylimidazole, and 1-cyanoethyl-2-undecylimidazole trimellitate. As the imidazole curing agent, one or a combination of two or more of the above specific examples can be used.

[0044] The lower limit of the content of the curing agent in the paste adhesive composition is, for example, preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, and even more preferably 0.3 parts by mass or more, per 100 parts by mass of the paste adhesive composition. The upper limit of the content of the curing agent in the paste adhesive composition is, for example, preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 5 parts by mass or less, per 100 parts by mass of the paste adhesive composition. When the content of the curing agent in the paste adhesive composition is within the above numerical range, the paste adhesive composition can be appropriately cured and shrunk.

[0045] [Radical polymerization initiator] The paste adhesive composition according to the present embodiment may contain, for example, a radical polymerization initiator. Specific examples of the radical polymerization initiator that can be used include azo compounds, peroxides, and the like. Of the specific examples above, one or a combination of two or more of the radical polymerization initiators can be used. Of the specific examples above, it is preferable to use, for example, a peroxide as the radical polymerization initiator.

[0046] Specific examples of the peroxides include bis(1-phenyl-1-methylethyl)peroxide, 1,1-bis(1,1-dimethylethylperoxy)cyclohexane, methyl ethyl ketone peroxide, cyclohexane peroxide, acetylacetone peroxide, 1,1-di(tert-hexylperoxy)cyclohexane, 1,1-di(tert-butylperoxy)-2-methylcyclohexane, 1,1-di(tert-butylperoxy)cyclohexane, 2,2-di(tert-butylperoxy)cyclohexane, Di)butane, n-butyl-4,4-di(tert-butylperoxy)valerate, 2,2-di(4,4-di(tert-butylperoxy)cyclohexane)propane, p-methane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, tert-butyl hydroperoxide, di(2-tert-butylperoxyisopropyl)benzene, α-dicumyl peroxide, 2,5-dimethyl-2,5 -Di(tert-butylperoxy)hexane, tert-butylcumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl 2,5-di(tert-butylperoxy)hexyne, diisobutyl peroxide, di(3,5,5-trimethylhexanoyl) peroxide, dilauryl peroxide, di(3-methylbenzoyl) peroxide, benzoyl(3-methylbenzoyl) peroxide, dibenzoyl peroxide, di(4-methylbenzoyl) peroxide, di-n-propyl propyl peroxydicarbonate, diisopropyl peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, di-sec-butyl peroxydicarbonate, cumyl peroxyneodecanate, 1,1,3,3-tetramethylbutyl peroxyneodecanate, tert-hexyl neodecanoate, tert-butyl peroxyneoheptanate, tert-hexyl peroxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanate, 2,5-dimethyl-2,Examples of peroxides include 5-di(2-diethylhexylperoxy)hexane, tert-butylperoxy-2-ethylhexanate, tert-hexyperoxyisopropyl monocarbonate, tert-butylperoxymaleic acid, tert-butylperoxy-3,5,5-trimethylhexanate, tert-butylperoxyisopropyl monocarbonate, tert-butylperoxy-2-ethylhexy monocarbonate, tert-hexylperoxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, tert-butylperoxyacetonate, tert-peroxy-3-methylbenzoate, tert-butylperoxybenzoate, tert-butylperoxyallyl monocarbonate, and 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone. The peroxides listed above can be used alone or in combination of two or more.

[0047] The lower limit of the content of the radical polymerization initiator in the paste adhesive composition is, for example, preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and even more preferably 0.2 parts by mass or more, per 100 parts by mass of the paste adhesive composition. The upper limit of the content of the radical polymerization initiator in the paste adhesive composition is, for example, preferably 5 parts by mass or less, more preferably 4 parts by mass or less, and even more preferably 3 parts by mass or less, per 100 parts by mass of the paste adhesive composition.

[0048] [Curing accelerator] The paste-like adhesive composition according to this embodiment may contain, for example, a curing accelerator that accelerates the reaction between the epoxy monomer or epoxy resin and the curing agent. Specific examples of curing accelerators include phosphorus-containing compounds such as organic phosphines, tetra-substituted phosphonium compounds, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds, and adducts of phosphonium compounds and silane compounds; amidines and tertiary amines such as 1,8-diazabicyclo[5.4.0]undecene-7 and benzyldimethylamine; and nitrogen-containing compounds such as quaternary ammonium salts of the above amidines or tertiary amines. The curing accelerators may be one or a combination of two or more of the above specific examples. Tetra-substituted phosphonium compounds are particularly preferred as curing accelerators, with tetraphenylphosphonium tetraphenylborate being particularly preferred.

[0049] The lower limit of the content of the curing accelerator in the paste adhesive composition is, for example, preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, per 100 parts by mass of the paste adhesive composition. The upper limit of the content of the curing accelerator in the paste adhesive composition is, for example, preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 6 parts by mass or less, per 100 parts by mass of the paste adhesive composition.

[0050] [Other ingredients] In addition to the above components, the paste adhesive composition according to the present embodiment may contain, for example, a stress reducing agent. Specific examples of stress reducing agents include silicone compounds such as silicone oil and silicone rubber; polybutadiene compounds such as polybutadiene maleic anhydride adducts; polycarbonate diol dimethacrylate; and acrylonitrile butadiene copolymer compounds. One or more of the above specific examples may be blended as the stress reducing agent. It is particularly preferable to use polybutadiene maleic anhydride adducts or polycarbonate diol dimethacrylate as the stress reducing agent.

[0051] The lower limit of the content of the low stress agent in the paste adhesive composition is, for example, preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1 part by mass or more, per 100 parts by mass of the paste adhesive composition. The upper limit of the content of the low stress agent in the paste adhesive composition is, for example, preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 5 parts by mass or less, per 100 parts by mass of the paste adhesive composition.

[0052] In addition to the above components, the paste adhesive composition according to this embodiment may contain a silane coupling agent to improve adhesion between the paste adhesive composition and a substrate. Specific examples of the silane coupling agent include vinyl silanes such as vinyltrimethoxysilane and vinyltriethoxysilane; epoxy silanes such as 3-glycidyloxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane; styryl silanes such as p-styryltrimethoxysilane; methacryl silanes such as 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropyltriethoxysilane; and 3-acryloxypropyltrimethoxysilane. Examples of suitable silane coupling agents include acrylic silanes such as N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, and aminosilanes such as N-phenyl-3-aminopropyltrimethoxysilane; isocyanurate silanes; alkyl silanes; ureidosilanes such as 3-ureidopropyltrialkoxysilane; mercaptosilanes such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane; isocyanate silanes such as 3-isocyanatepropyltriethoxysilane; and 3-(trimethoxysilyl)propyl methacrylate. The silane coupling agents may be selected from the above specific examples, and may be used alone or in combination of two or more.

[0053] The lower limit of the content of the silane coupling agent in the paste adhesive composition is, for example, preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and even more preferably 0.2 parts by mass or more, per 100 parts by mass of the paste adhesive composition. The upper limit of the content of the silane coupling agent in the paste adhesive composition is, for example, preferably 5 parts by mass or less, more preferably 4 parts by mass or less, and even more preferably 3 parts by mass or less, per 100 parts by mass of the paste adhesive composition.

[0054] In addition to the above components, the paste adhesive composition according to the present embodiment may also contain, for example, a solvent. Specific examples of the solvent include methyl carbitol, ethyl carbitol, butyl carbitol, methyl carbitol acetate, ethyl carbitol acetate, butyl carbitol acetate, acetylacetone, methyl isobutyl ketone (MIBK), anone, diacetone alcohol, ethyl cellosolve, methyl cellosolve, butyl cellosolve, ethyl cellosolve acetate, methyl cellosolve acetate, butyl cellosolve acetate, ethyl alcohol, propyl alcohol, butyl alcohol, pentyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, and propylene glycol monomethyl ether. Alcohols such as glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, methyl methoxybutanol, α-terpineol, β-terpineol, γ-terpineol, terpineol (a mixture of α, β, and γ), dihydroterpineol, hexylene glycol, benzyl alcohol, 2-phenylethyl alcohol, isopalmityl alcohol, isostearyl alcohol, lauryl alcohol, ethylene glycol, propylene glycol, or glycerin; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol (4-hydroxy-4-methyl-2-pentanone), 2-octanone, isophorone (3,5,5-trimethyl-2-cyclohexen-1-one), or diisobutyl ketone (2,6-dimethyl-4-heptanone);Esters such as ethyl acetate, butyl acetate, diethyl phthalate, dibutyl phthalate, acetoxyethane, methyl butyrate, methyl hexanoate, methyl octanoate, methyl decanoate, methyl cellosolve acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, 1,2-diacetoxyethane, tributyl phosphate, tricresyl phosphate, or tripentyl phosphate; tetrahydrofuran, dipropyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, ethoxy Examples of solvents that can be used include ethers such as diethyl ether, 1,2-bis(2-diethoxy)ethane, and 1,2-bis(2-methoxyethoxy)ethane; ester ethers such as 2-(2-butoxyethoxy)ethane acetate; ether alcohols such as 2-(2-methoxyethoxy)ethanol; hydrocarbons such as toluene, xylene, n-paraffin, isoparaffin, dodecylbenzene, turpentine, kerosene, and diesel; nitriles such as acetonitrile and propionitrile; amides such as acetamide and N,N-dimethylformamide; low-molecular-weight volatile silicone oils; and volatile organic modified silicone oils. The solvents listed above can be used alone or in combination.

[0055] The lower limit of the solvent content in the paste adhesive composition is, for example, preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 2 parts by mass or more, per 100 parts by mass of the paste adhesive composition. The upper limit of the solvent content in the paste adhesive composition is, for example, preferably 5 parts by mass or less, more preferably 4 parts by mass or less, and even more preferably 3 parts by mass or less, per 100 parts by mass of the paste adhesive composition.

[0056] [Method of producing a paste-like adhesive composition] A method for producing a paste adhesive composition according to this embodiment will now be described. The method for producing a paste adhesive composition includes a mixing step of mixing the above-described raw material components to produce a mixture, and a degassing step of removing air contained in the mixture.

[0057] <Mixing process> In the mixing step, the raw material components are mixed to prepare a mixture. The mixing method is not limited, and for example, a three-roll mill, a mixer, etc. can be used. In this way, the raw material components are mixed to obtain a mixture.

[0058] <Defoaming process> In the degassing step, air contained in the mixture is removed. The method for removing air contained in the mixture is not limited, and the removal can be performed, for example, by leaving the mixture under vacuum. This results in a paste-like adhesive composition.

[0059] [Application] The use of the paste adhesive composition according to this embodiment will be described. The paste adhesive composition according to this embodiment is used, for example, to bond a substrate to a semiconductor element. Examples of semiconductor elements include semiconductor packages and LEDs. Compared to conventional paste adhesive compositions, the paste adhesive composition according to this embodiment can achieve both good adhesion and reduced fillet creep. This makes it more suitable for use in bonding semiconductor elements with a thickness of 200 μm or less. [Example]

[0060] The present invention will be described in detail below using examples, but the present invention is not limited to the descriptions of these examples.

[0061] Table 1 shows the parts by mass of each raw material component in each of the Examples and Comparative Examples relative to 100 parts of the paste adhesive composition. (polymerizable compound) Polymerizable compound 1: 1,3-bis(3-glycidyloxypropyl)tetramethyldisilazane (Momentive Performance Materials Japan: TSL-9906) Polymerizable compound 2: Bisphenol-F-diglycidyl ether (Nippon Kayaku Co., Ltd.) Polymerizable compound 3: t-butylphenyl glycidyl ether (Nippon Kayaku Co., Ltd.) Polymerizable compound 4: 4-(2,3-epoxypropan-1-yloxy)N,N-bis(2,3-epoxypropan-1-yl)-2-methylaniline (Osaka Soda Co., Ltd.) Polymerizable compound 5: m,p-cresyl glycidyl ether (Sakamoto Pharmaceutical Co., Ltd.: mp-CGE) Polymerizable compound 6: acrylic acid polymer (Toagosei Co., Ltd.: ARUFON UG4035) Polymerizable compound 7: 2-phenoxyethyl methacrylate (Kyoeisha Chemical Co., Ltd.) Polymerizable compound 8: Propoxylated bisphenol A diacrylate (Shin-Nakamura Chemical Co., Ltd.: A-BPP-3) Polymerizable compound 9: hexane-1,6-diol bis(2-methyl acrylate) (Kyoeisha Chemical Co., Ltd.: 1,6HX) (curing accelerator) Curing accelerator 1: Tetraphenylphosphonium tetraphenylborate (Hokuko Chemical Industry Co., Ltd.: TPP-K) (hardening agent) Hardener 1: Dihydroxydiphenylmethane (DIC Corporation: DIC-BPF) Hardener 2: Biphenol (Seishin Enterprise Co., Ltd.) Hardener 3: 2-phenyl-4,5-dihydroxymethylimidazole (Shikoku Chemicals Co., Ltd.: 2PHZ-PW) Hardener 4: 2,4-diamino-6-(2'-methylimidazolyl-1-)ethyl-s-triazine (Shikoku Chemicals Co., Ltd.: 2MZA-PW) Curing agent 5: 2-undecylimidazole (Shikoku Chemicals: C11Z) (Radical polymerization initiator) Peroxide 1: Bis(1-phenyl-1-methylethyl) peroxide (Perkadox BC, manufactured by Nouryon) (particulate filler) Silver powder 1: Flake silver powder (Fukuda Metal Foil and Powder Co., Ltd.: D50: 8.0 μm, specific surface area: 0.27 m 2 / g, tap density: 3.3g / cm 3 ) Silver powder 2: Spherical silver powder (DOWA Electronics Co., Ltd.: D50: 0.7, specific surface area: 1.05 m 2 / g, tap density: 5.3g / cm 3 )

[0062] [Table 1]

[0063] [Table 2]

[0064] <Preparation of Paste-like Adhesive Composition> For each of the Examples and Comparative Examples, a paste-like adhesive composition was obtained by the following procedure. First, the raw material components, excluding silver powder, in the amounts shown in Table 1 were kneaded with a solvent in a three-roll mill at room temperature. The solvent and silver powder were then kneaded in the three-roll mill and degassed to obtain a paste-like adhesive composition.

[0065] For the paste adhesive compositions of Examples 4-6, polymerizable compound 6 was preliminarily dissolved in a portion of polymerizable compound 7 (see the upper row of the column for polymerizable compound 7 in Table 1). Then, the remaining raw material components, excluding silver powder, including polymerizable compound 7 (see the lower row of the column for polymerizable compound 7 in Table 1), were kneaded with a solvent in a three-roll mill at room temperature, and then the solvent and silver powder were kneaded in the three-roll mill to obtain a paste adhesive composition.

[0066] <Measurement> The following values ​​were measured for the paste adhesive composition of each example. The measured values ​​are shown in Table 1.

[0067] (η5) The value measured at 25°C using a Brookfield viscometer at a rotation speed of 5 rpm was taken as η5.

[0068] (η 0.5 / η5) At 25°C, the value measured using a Brookfield viscometer at a rotation speed of 0.5 rpm is η 0.5 Then, from the measured value, η 0.5 The value of / η5 was calculated.

[0069] (coverage rate) The coverage was measured based on the following condition 1. [Condition 1] 1. Prepare the following wafers and substrates: Wafer (material: silicon, length, width, height: 4mm x 4mm x 0.2mm) Substrate (lead frame, material: Cu) 2. The paste adhesive composition is applied to a rectangular area (4 mm x 4 mm) on the substrate where the wafer is to be placed, along the diagonal of the rectangular area, to a length of 4.5 mm, a width of 0.8 mm, and a thickness of 0.1 mm. 3. The wafer is placed on the rectangular area to which the paste adhesive composition has been applied. 4. Five minutes after the wafer is mounted, the ratio [%] of the rectangular area to the entire rectangular area that is coated with the paste adhesive composition is defined as the coverage rate.

[0070] (Capillary fillability) The capillary fill ability was measured under the following condition 2. [Condition 2] 1. Prepare the following wafers and substrates: Wafer (material: silicon, length, width, height: 4mm x 4mm x 0.2mm) Substrate (lead frame, material: Cu) 2. The paste adhesive composition is applied to a rectangular area (4 mm x 4 mm) on the substrate where the wafer is to be placed, along the diagonal of the rectangular area, to a length of 4.5 mm, a width of 0.8 mm, and a thickness of 0.1 mm. 3. The wafer is placed on the rectangular area to which the paste adhesive composition has been applied. 4. The time t [min] from when the wafer is mounted until the proportion of the rectangular area coated with the paste adhesive composition reaches 95% of the entire rectangular area is defined as the "capillary fillability."

[0071] In addition, the ratio of the rectangular area to which the paste adhesive composition was applied to the entire rectangular area under the above-mentioned conditions 1 and 2 was calculated by image processing of an image taken of the substrate from a vertical direction using an imaging device (X-ray visualization device manufactured by Shimadzu Corporation).

[0072] <Evaluation> The paste adhesive composition of each example was evaluated as follows.

[0073] (Adhesiveness) The paste adhesive composition of each example and comparative example was applied to a rectangular area (4 mm x 4 mm) on the substrate where the wafer was to be placed, along the diagonal of the rectangular area, to a length of 4.5 mm, a width of 0.8 mm, and a thickness of 0.1 mm. The substrates and wafers used were as follows: Wafer (material: silicon, length, width, height: 4mm x 4mm x 0.2mm) Substrate (lead frame, material: Cu) Thereafter, the paste adhesive composition was cured at 100° C. for 5 minutes, and the wafer was adhered to the substrate, and the adhesiveness was evaluated. The adhesive properties of the paste adhesive compositions of each example are evaluated in Table 1. In Table 1, "good" indicates that the adhesion was sufficiently strong, and "bad" indicates that the adhesion was not sufficiently strong.

[0074] (fillet creeping up) The paste adhesive composition of each example and comparative example was applied to a rectangular area (4 mm x 4 mm) on the substrate where the wafer was to be placed, along the diagonal of the rectangular area, to a length of 4.5 mm, a width of 0.8 mm, and a thickness of 0.1 mm. The substrates and wafers used were as follows: Wafer (material: silicon, length, width, height: 4mm x 4mm x 0.2mm) Substrate (lead frame, material: Cu) Thereafter, the paste adhesive composition was cured at 100°C for 5 minutes, the wafer was bonded to the substrate, and the fillet creep was evaluated. The evaluation of fillet creep for the paste adhesive composition of each example is shown in Table 1. In Table 1, "good" indicates that the fillet creep height was less than 100 μm, and "bad" indicates that the fillet creep height was 100 μm or more.

[0075] As described above, it was confirmed that the paste-like adhesive composition according to this embodiment can achieve both good adhesion and reduced fillet creeping. Furthermore, the evaluation results of Examples 4 to 6 and Comparative Example 5 confirmed that pre-dissolving polymerizable compound 6 in a portion of polymerizable compound 7 can reduce fillet creeping.

Claims

1. A paste-like adhesive composition used for adhering a semiconductor element having a thickness of 200 μm or less to a substrate, a polymerizable compound; a particulate filler; Including, Viscosity η measured at 25°C using a Brookfield viscometer at a rotation speed of 5 rpm ５ is 15,000 mPa s or more and 50,000 mPa s or less, Viscosity η measured at 25°C using the Brookfield viscometer at a rotation speed of 0.5 rpm ０．５ and η ５ η is the ratio of ０．５ / η ５ is 1.5 or more and 4.0 or less.

2. 2. The paste adhesive composition according to claim 1, A paste-like adhesive composition having a coverage of 95% or more as defined by the following condition 1. [Condition 1] 1. Prepare a wafer (material: silicon, length, width, height: 4 mm x 4 mm x 0.2 mm) and a substrate.

2. The paste adhesive composition is applied to a rectangular area (4 mm x 4 mm) on the substrate where the wafer is to be placed, along the diagonal of the rectangular area, to a length of 4.5 mm, a width of 0.8 mm, and a thickness of 0.1 mm.

3. The wafer is placed on the rectangular area to which the paste adhesive composition has been applied.

4. Five minutes after the wafer is mounted, the ratio [%] of the rectangular area to the entire rectangular area that is coated with the paste adhesive composition is defined as the coverage rate.

3. 3. The paste adhesive composition according to claim 1 or 2, A paste-like adhesive composition having a capillary fill property of 5 min or less as defined by the following condition 2. [Condition 2] 1. Prepare a wafer (material: silicon, length, width, height: 4 mm x 4 mm x 0.2 mm) and a substrate.

2. The paste adhesive composition is applied to a rectangular area (4 mm x 4 mm) on the substrate where the wafer is to be placed, along the diagonal of the rectangular area, to a length of 4.5 mm, a width of 0.8 mm, and a thickness of 0.1 mm.

3. The wafer is placed on the rectangular area to which the paste adhesive composition has been applied.

4. The time t [min] from when the wafer is mounted until the proportion of the rectangular area coated with the paste adhesive composition relative to the entire rectangular area reaches 95% is defined as "capillary fillability."

4. 3. The paste adhesive composition according to claim 1 or 2, A paste-like adhesive composition, wherein the polymerizable compound comprises a compound having an epoxy group or a compound having a polymerizable double bond group.

5. 5. The paste adhesive composition according to claim 4, A paste-like adhesive composition, wherein the polymerizable compound comprises an acrylic acid ester.

6. 3. The paste adhesive composition according to claim 1 or 2, A paste adhesive composition, wherein the particulate filler is conductive particles.

7. 7. The paste adhesive composition according to claim 6, A paste adhesive composition in which the particulate filler has at least a portion of its surface made of silver or copper.

8. 3. The paste adhesive composition according to claim 1 or 2, The paste adhesive composition, wherein the particulate filler is insulating particles.

9. 9. A paste adhesive composition according to claim 8, The particulate filler is a paste adhesive composition comprising at least one material selected from the group consisting of silicon dioxide, boron nitride, alumina, and an organic material.

10. 3. The paste adhesive composition according to claim 1 or 2, The paste adhesive composition, wherein the particulate filler is composed of at least one of spherical particles, polygonal particles, flake-like particles, dendritic particles, and scale-like particles.

11. 3. The paste adhesive composition according to claim 1 or 2, The particulate filler has a particle diameter D50 of 0.1 μm or more and 20 μm or less, at which the cumulative frequency is 50% in a volume-based cumulative frequency distribution curve measured using a laser diffraction particle size distribution measuring device.

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